Touch control one of the simplest and most convenient man-machine interaction modes available at present. Therefore, touchscreens are increasingly used in a variety of electronic products. Based on different working principles and information transmission medium, touchscreen products can be divided into four types: infrared touchscreens, capacitive touchscreens, resistance touchscreens, and surface acoustic wave touchscreens, among which, capacitive touchscreens have become the mainstream touchscreens currently due to various advantages thereof, such as long service lives, high transmittance, capability in supporting multi-touch control, etc.
Capacitive touchscreens can be surface capacitive or projected capacitive, wherein projected capacitive touchscreens can further be self-capacitive or mutual-capacitive. In a mutual-capacitive touchscreen, a sensing electrode Rx and a scanning electrode Tx are made on a surface of a substrate (usually a glass substrate) with indium tin oxide (ITO for short), wherein a coupling capacitor would be formed where two groups of electrodes cross each other. That is, the two groups of electrodes constitute two poles of the coupling capacitor, respectively. When a capacitive screen is touched with a finger, the coupling between two electrodes in the vicinity of a touch point would be affected, thereby altering the value of a coupling capacitance therebetween. The coordinate of each touch point can be calculated based on two-dimensional capacitive variation data of a mutual-capacitive touchscreen. Therefore, even if there is a plurality of touch points on the screen, the real coordinate of each of the touch points can be calculated.
Currently, there substantially exist two varieties of mutual-capacitive touchscreens. One is termed a double layer ITO (DITO for short) mutual-capacitive touchscreen, in which the sensing electrode Rx and the scanning electrode Tx are manufactured with two layers of ITO conductive materials and arranged on two parallel but non-coplanar planes, respectively. This type of touchscreens has to be manufactured through a complex manufacturing procedure and yield rates thereof are restricted thereby. The other is termed a single layer ITO (SITO for short) mutual-capacitive touchscreen, in which the sensing electrode Rx and the scanning electrode Tx are arranged on one and the same plane. The manufacturing procedure of a SITO mutual-capacitive touchscreen is simpler than that of a DITO mutual-capacitive touchscreen, and therefore SITO mutual-capacitive touchscreens have become the mainstream products currently.
It has been found that according to an existing drive mode, scanning electrodes Tx are scanned sequentially by line at a relatively low scanning frequency, thereby preventing the SITO mutual-capacitive touchscreen from being scanned at a high frequency. As a result, touch signals are scanned with low accuracy.